select() vs. pipes (was [Python-Dev] Re: PEP 324 (process module))

[Bob Ippolito]

On Aug 4, 2004, at 4:03 PM, Chris McDonough wrote:

> On Wed, 2004-08-04 at 15:01, Peter Astrand wrote:
>> So, there is no problem with using select() on pipes when 
>> communicating
>> with a subprocess. It works great. Take a look at (my) process.py's
>> communicate() method for some inspiration.
>
> I've actually looked at it and it's quite nice, but it doesn't do one
> thing that I'd like to see as part of a process stdlib library.  The 
> use
> case I'm thinking of is one where a long-running program needs to
> monitor the output of many other potentially long-running processes,
> doing other things in the meantime.  This kind of program tends to use
> select as a part of a mainloop where there might be other things going
> on (like handling network communications to/from sockets, updating a
> GUI, etc).  Also, the output from child stderr and stdout potentially
> never end because the child process(es) may never end.

Twisted handles this quite well already.  The stdlib doesn't really do 
much to support this style of programming.

-bob